Re: [PATCH] linux/pci.h: add a dummy implement for pci_clear_master()

[Bjorn Helgaas <helgaas@kernel.org>]

On Tue, May 30, 2023 at 06:16:55PM +0800, Sui Jingfeng wrote:
> As some arch(m68k for example) doesn't have config_pci enabled, drivers[1]
> call pci_clear_master() without config_pci guard can not built.
> 
>    drivers/gpu/drm/etnaviv/etnaviv_pci_drv.c:
>    In function 'etnaviv_gpu_pci_fini':
> >> drivers/gpu/drm/etnaviv/etnaviv_pci_drv.c:32:9:
>    error: implicit declaration of function 'pci_clear_master';
>    did you mean 'pci_set_master'? [-Werror=implicit-function-declaration]
>       32 |         pci_clear_master(pdev);
>          |         ^~~~~~~~~~~~~~~~
>          |         pci_set_master
>    cc1: some warnings being treated as errors
> 
> [1] https://patchwork.freedesktop.org/patch/539977/?series=118522&rev=1

I don't mind adding a stub if it's needed, but I don't understand why
it's needed here.  The caller is in etnaviv_pci_drv.c, and if I
understand the patch at [1], etnaviv_pci_drv.c is only compiled when
CONFIG_PCI=y.

Bjorn

[1] https://lore.kernel.org/all/20230530160643.2344551-6-suijingfeng@loongson.cn/

> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202305301659.4guSLavL-lkp@intel.com/
> Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
> ---
>  include/linux/pci.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index d0c19ff0c958..71c85380676c 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1904,6 +1904,7 @@ static inline int pci_dev_present(const struct pci_device_id *ids)
>  #define pci_dev_put(dev)	do { } while (0)
>  
>  static inline void pci_set_master(struct pci_dev *dev) { }
> +static inline void pci_clear_master(struct pci_dev *dev) { }
>  static inline int pci_enable_device(struct pci_dev *dev) { return -EIO; }
>  static inline void pci_disable_device(struct pci_dev *dev) { }
>  static inline int pcim_enable_device(struct pci_dev *pdev) { return -EIO; }
> -- 
> 2.25.1
>